Method and apparatus for reducing organic depletion during non-processing time periods

Abstract

Embodiments of the invention generally provide an apparatus and method for replenishing organic molecules in an electroplating bath. The replenishment process of the present invention may occur on a real-time basis, and therefore, the concentration of organics minimally varies from desired concentration levels. The replenishment method generally includes conducting pre-processing depletion measurements in order to determine organic depletion rates per current density applied in the electroplating system. Once the organic depletion rates per current density are determined, these depletion rates may be applied to an electroplating processing recipe to calculate the volume of organic depletion per recipe step. The calculated volume of organic depletion per recipe step may then be used to determine the volume of organic molecule replenishment per unit of time that is required per recipe step in order to maintain a desired concentration of organics in the plating solution. The calculated replenishment volume may then be added to the processing recipe so that the replenishment process may occur at real-time during processing periods. The apparatus generally includes a selectively actuated valve in communicaiton with a fluid delivery line, wherein the valve is configured to fluidly isolate a plating cell during a non-processing time period. The valve may be controlled by a system controller, and thus, the fluid level in the cell may be controlled during a non-processing time period.

1. An electrochemical plating apparatus, comprising:
 a plating cell configured to contain a plating bath below an overflow outlet;  
 a substrate support member positioned in the plating cell and configured to selectively contact the plating bath with a substrate secured thereto;  
 a fluid supply line in fluid communication with the plating cell;  
 a selectively actuated check valve positioned in the fluid supply line;  
 an anode in the plating cell; and  
 a bleed line in fluid communication with the plating cell at a position in the plating cell between the overflow outlet and the anode.  
 
     
     
       2. The electrochemical plating apparatus of  claim 1 , wherein the bleed line is positioned in a side wall of the plating cell and is configured to drain a portion of the plating bath. 
     
     
       3. The electrochemical plating apparatus of  claim 2 , wherein the bleed line is positioned in the side wall proximate a top portion of an anode positioned in the plating cell. 
     
     
       4. The electrochemical plating apparatus of  claim 3 , wherein the bleed line is configured to drain the plating cell, while leaving a sufficient amount of electrolyte in the plating cell to immerse the anode. 
     
     
       5. The electrochemical plating apparatus of  claim 1 , wherein the bleed line further comprises a selectively actuated bleed valve. 
     
     
       6. The electrochemical plating apparatus of  claim 1 , further comprising a microprocessor-type controller configured to regulate operational characteristics of the electrochemical plating apparatus. 
     
     
       7. The electrochemical plating apparatus of  claim 6 , wherein the microprocessor-type controller is configured to close the selectively actuated check valve in the fluid supply line and open the bleed line to drain a portion of the plating cell. 
     
     
       8. The electrochemical plating apparatus of  claim 7 , wherein the controller is configured to drain a portion of the plating cell during non-processing time periods by opening a selectively actuated bleed valve positioned in the bleed line. 
     
     
       9. An electrochemical plating apparatus, comprising:
 a plating cell configured to contain a plating bath below an overflow outlet;  
 a substrate support member positioned in the plating cell and configured to contact a substrate with the plating bath;  
 a fluid supply line in fluid communication with the plating cell;  
 an anode in the plating cell; and  
 a bleed line in fluid communication with the plating cell at a position in the plating cell between the overflow outlet and the anode.  
 
     
     
       10. The electrochemical plating apparatus of  claim 9 , wherein the bleed line is configured to drain a portion of the plating bath from the plating cell, while leaving a sufficient amount of plating bath in the plating cell to immerse the anode. 
     
     
       11. The electrochemical plating apparatus of  claim 9 , further comprising a check valve in the fluid supply line. 
     
     
       12. The electrochemical plating apparatus of  claim 11 , wherein the check valve is selectively actuated. 
     
     
       13. The electrochemical plating apparatus of  claim 9 , further comprising a valve in the bleed line. 
     
     
       14. The electrochemical plating apparatus of  claim 13 , wherein the valve in the bleed line is selectively actuated. 
     
     
       15. The electrochemical plating apparatus of  claim 9 , further comprising a microprocessor-type controller configured to regulate operational characteristics of the electrochemical plating apparatus. 
     
     
       16. The electrochemical plating apparatus of  claim 15 , further comprising a valve in the fluid supply line, wherein the microprocessor-type controller is configured to close the valve in the fluid supply line and open the bleed line to drain a portion of the plating bath from the plating cell. 
     
     
       17. The electrochemical plating apparatus of  claim 9 , wherein the microprocessor-type controller is configured to drain a portion of the plating bath from the plating cell during non-processing time periods by opening a selectively actuated bleed valve positioned in the bleed line.